The present invention relates to a micro fluorescent X-ray analyzing device for performing elemental analysis by making primary X rays into a thin flux and measuring fluorescent X rays that are generated from a fine region.
Concerning a conventional fluorescent analyzer, under the understanding that the region where primary X-rays are radiated is several tens of millimeters in diameter and the substances that exist in the world of nature have no uniformity as viewed in terms of their quality, measurement thereof is performed by the radiation area being widened to thereby perform averaging of such non-uniform qualities and thereby enhance the degree of accuracy. Under this circumstance, the KEVEX company in the United States: device name--Omicron and the TECHNO company in Japan: device name TREX 650 have recently developed fluorescent X-ray analyzing devices which are used for measurement in a region of the sub-millimeter order and which are called "micro fluorescent analyzing devices". FIG. 3 and FIG. 4 show the conventional micro fluorescent analyzing devices. In FIG. 3 and FIG. 4, 1 denotes an X-ray generating portion for generating primary X-rays, i.e. an X-ray tube, 2 denotes the primary X-rays that are generated from the X-ray tube, 3 denotes a capillary tube for restricting the primary X-rays into a high luminance of thin flux or a collimator of hollow metallic cylinder, 7 denotes a sample, 8 denotes fluorescent X-rays, 4 denotes a semiconductor detector which detects fluorescent X-rays 8, 6 denotes a cooling unit which cools semiconductor 4, 9 denotes a counting circuit for processing a signal of the fluorescent X-rays 8 that have been measured by the semiconductor detector 4, and 10 denotes a data processing portion for performing quantitative calculations, mapping display, etc. with respect to the measured data. In FIG. 4, 12 denotes an X-ray capillary tube (light receiving portion).
Also, while, conventionally, SEM-EDX or EPMA and XMA (X-ray m microanalysis) that utilize electronic microscopes were unavoidably forced to be applied to the elemental analysis or mapping analysis (distribution analysis) of a fine portion, since each of these analyses utilizes electron beams as the probe, such analyses involved therein the operational problems of necessitating the use of vacuum and of necessitating charge-up at a time of measurement of insulative material. By using X rays as the probe, there is the merit that the problem with insulative material can be settled. However, in the conventional micro fluorescent X-ray analyzing the devices, semiconductor detector 4 for measuring the fluorescent X-rays is formed into a probe configuration and is limited to unidirectional detection only. Accordingly, in order to approach the detector to the region from which the fluorescent X-rays are generated for the purpose of effectively measuring the intensity of a small amount of fluorescent X-rays, it is necessary to make small the forward end of the probe, i.e. detection area. However, when decreasing the detection area, the solid angle of detection of the fluorescent X-rays becomes small, with the result that there arises the problem of a sufficiently high level of intensity being not obtained. If the detection area is made large in order to make the solid angle large, the forward end of the probe becomes remote from the generation region of the fluorescent X-rays by reason of the structure and disposition, with the result that there arises the problem of a sufficiently high level of intensity being not obtained according to the inverse-square law of the distance.
Also, where fluorescent X-rays are measured from one direction, even if the primary X-rays are made into a thin flux with respect to a fine region, there arises the problem of the resulting fluorescent X rays inconveniently having a bias and broadening with directionality according to the detection angle. In the case of the X-ray analyzing device that is excited by electron beams, since electron beams cannot be deeply entered into because of having a certain value of weight and therefore have a short range that is of the sub .mu.m order, the depth from which the X-rays are generated is several .mu.m or less with the result that the X-rays are generated from the surface of a very small depth. Therefore, even when the detection angle exists, no difference is made within the fine region itself. However, since X-rays have a great power of transmission, even when the radiation area of X-rays on the surface of the sample is reduced to a value that is of the .mu.m order, the depth from which the fluorescent X-rays are generated increases to a value that is of the order of several tens of .mu.m to several mm although differing according to the coexistent elements. For this reason, in the case of the micro fluorescent X-ray analyzer, when detection is unidirectionally performed, there inconveniently arises the problem of bias and broadening.
On the other hand, there is also a technique wherein an X-ray capillary tube 12 shown in FIG. 4 is also disposed on the detection side in order to eliminate the effect of the broadening of the fluorescent X-rays that are generated from a fine region. However, in this case, because of the solid angle becoming too small, there was the problem that a sufficiently high level of detection intensity was not obtained.
The present invention has been made in order to solve the problems that are involved in the conventional micro fluorescent X-ray analyzer and provides a micro fluorescent X-ray analyzer that has been arranged to eliminate the effect of the bias and broadening with regard to the fluorescent X-rays that are generated from a fine region.